I21.09 — ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall
I21.09 is a billable, specific ICD-10-CM code for st elevation (stemi) myocardial infarction involving other coronary artery of anterior wall. It is valid for submission on a claim.
Inclusion terms
Alternative wordings a physician may use in the chart for this same code.
- Acute transmural myocardial infarction of anterior wall
- Anteroapical transmural (Q wave) infarction (acute)
- Anterolateral transmural (Q wave) infarction (acute)
- Anteroseptal transmural (Q wave) infarction (acute)
- Transmural (Q wave) infarction (acute) (of) anterior (wall) NOS
Risk adjustment
I21.09 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 228 Acute Myocardial Infarction0.252 RAF
Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.
Medicare coverage
I21.09 is named in 67 Medicare coverage policies — 67 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A52458Automatic External Defibrillators - Policy Article
- A52458Automatic External Defibrillators - Policy Article
- A52850Billing and Coding: Cardiac Catheterization and Coronary Angiography
- A52850Billing and Coding: Cardiac Catheterization and Coronary Angiography
How I21.09 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to I21.09.
- Infarct, infarction›myocardium, myocardial›ST elevation›anterior(anteroapical) (anterolateral) (anteroseptal) (Q wave) (wall)
- Infarct, infarction›myocardium, myocardial›transmural›anterior NEC(anteroapical) (anterolateral) (anteroseptal) (Q wave) (wall)
- Infarct, infarction›myocardium, myocardial›ST elevation›involving›coronary artery of anterior wall NEC
Related codes at this level
Codes that share I21.0. If I21.09 is not quite right, the correct code is usually one of these.
Questions about I21.09
- Is I21.09 a billable ICD-10-CM code?
- Yes. I21.09 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does I21.09 sit in the tabular list?
- Diseases of the circulatory system (I00-I99), in the block Ischemic heart diseases (I20-I25).